The present invention relates to a wire rope which comprises several strands twisted together around a fiber or steel rope core and which contains a durable marker.
It is difficult to distinguish qualitative characteristics of wire ropes, such as strength, metal composition, resistance to corrosion, etc., simply by the outward appearance of the ropes. Therefore, attempts have been made to mark the individual wire ropes according to the various technical applications for which they are intended. However, quite a number of problems have come up in trying to realize this aim.
For example, when ropes are guided over rollers, the individual strands are shifted relative to the core, whereby high specific pressures are observed. In general, the conventionally used markers are damaged or even destroyed by these mechanical stresses.
Furthermore, wire ropes are often treated with greases, lubricating agents or impregnating agents during use, and, of course, the markers must not be attacked by these substances. The lubricating and impregnating agents also cause the metal dust forming due to the mechanical stress to adhere. Consequently, the wire ropes turn black after a short time of use, and often the color of the marker is no longer recognizable. The steel dust in turn causes mechanical stresses which in many cases are not sustained by the conventional markers.
Under normal operating conditions, the wire ropes generally reach temperatures of about 100.degree. C., but under extreme stresses, temperatures up to 200.degree.-300.degree. C. can occur. At these extremely high temperatures, conventionally used markers are frequently stained or charred.